Considering solar PV for your household

The following information may help you think about this question. Contact local solar providers for an assessment of your situation including a financial analysis considering incentives and tax advantages.

• A properly located (free from shade) stationary 1 kW-ac (alternating current) system can be expected to produce about 1200 kWh in a year in Wisconsin. 
• The average Wisconsin single-family home uses nearly 10,000 KWH of electricity a year.  An 8-10 kWh PV system could generate the amount of electricity used by the average Wisconsin household in a year.  If a household has excess electricity production for a month, it can carry over that excess production for use at a future time.
• A one kW system needs about 60 square feet of solar collection surface which will consist of three modules with each about 66” high and 40” wide.  Each module weighs about 50 lbs. and contains 60 individual photovoltaic cells. 
• A 10 kWh system needs about 600 square foot of sloped roof space (for example a roof area of ten feet high by sixty feet long).  Many houses could have enough roof space to generate about half of their electrical usage.

The preceding and following paragraph assumes a sloped roof typically found on homes. Note that a south facing roof is most desirable situation. A flat roof would require more mounting hardware. 

For a sloped roof mounted PV system, the four main components are:

Solar panels (expected life of 25 + years)
Inverters (convert direct current from the solar panels to alternating current and are expected to last 10-20 years before replacement)
Racking (holds panels on the roof or ground and expected to last 25+ years) 
Balance of system (includes conduit, wire, electrical breakers etc.) 

Currently, the installed cost of a sloped roof mounted solar PV system ranges from $2,200 to $2,400 per KW of rated capacity for small (10 KW or less) system.